#!/usr/bin/env python3
# -*- coding: utf-8 -*-

__author__ ='Michael liao'

'''
JSON API definition
'''

import json,logging,inspect,functools


class Page(object):
    '''
    Page object for display pages.
    '''

    def __init__(self,item_count,page_index=1,page_size=10):
        self.item_count=item_count
        self.page_size=page_size
        self.page_count= item_count // page_size + (1 if item_count%page_size>0 else 0)
        if(item_count==0) or (page_index>self.page_count):
            self.offset=0
            self.limit=0
            self.page_index=1
        else:
            self.page_index=page_index
            self.offset=self.page_size*(page_index-1)
            self.limit=self.page_size
        self.has_next=self.page_index<self.page_count
        self.has_previous=self.page_index>1

    def __str__(self):
        return 'item_count: %s, page_count: %s, page_index: %s, page_size: %s, offset: %s, limit: %s' % (self.item_count, self.page_count, self.page_index, self.page_size, self.offset, self.limit)
    __repr__=__str__


class APIError(Exception):
    '''
    the base APIError which contains error(required), data(optional) and message(optional).
    '''
    def __init__(self, error,data='', message=''):
        super(APIError,self).__init__(message)
        self.error=error
        self.data=data
        self.message=message
class APIValueError(APIError):
    '''
    Indicate the input value has error or invalid. The data specifies the error field of input form.
    '''
    def __init__(self, field, message=''):
        super(APIValueError, self).__init__('value:invalid', field, message)

class APIResourceNotFoundError(APIError):
    '''
    Indicate the resource was not found. The data specifies the resource name.
    '''
    def __init__(self, field, message=''):
        super(APIResourceNotFoundError, self).__init__('value:notfound', field, message)

class APIPermissionError(APIError):
    '''
    Indicate the api has no permission.
    '''
    def __init__(self, message=''):
        super(APIPermissionError, self).__init__('permission:forbidden', 'permission', message)